Linkage of diagenesis to depositional environments and stratigraphy in the northern part of the Baltic basin

Abstract

The spatial and temporal distribution of carbonate cementation was investigated in Devonian siliciclastic rocks of the northern part of the Baltic basin, using geochemical (oxygen and carbon stable isotope, microprobe and bulk chemical analyses), optical, scanning electron and cathodoluminescence microscope methods. Carbonate cementation in the studied rocks is dolomitic and only rarely calcitic. Dolomite cementation occurs as laterally persistent zones, lenses or concretionary forms. Carbonate-cemented beds are the most common at the level of the maximum flooding surface and within the regressive system tract sediments. Levels of concretionary cementation with dolocrete features possibly mark the position of subaerial unconformities. Interpretation of dolomite δ13C and δ18O values suggests marine and/or mixed marine-meteoric origin of diagenetic fluids. Marine origin of fluids is interpreted in the diagenetic alteration of siliciclastic interlayers in the Leivu and Kernave sequences that were cemented penecontemporaneously with early diagenetic dolomitization of carbonate rocks. The siliciclastic intervals of the Vadja Formation and partly of the Leivu Formation were cemented somewhat later with dolomite precipitated from mixed marine-meteoric pore water. Carbon isotopic values suggest that carbon was mainly derived from marine sources, except in the Pärnu Formation where negative δ13C values of dolomite indicate that carbon was derived from oxidation of organic materials

Temporal evolution, petrography and composition of dolostones in the Upper Devonian Plavinas Regional Stage, southern Estonia and northern Latvia

“…The major part of the section is dolomitized. Petrographically and geochemically the dolostones of the Plavinas RS differ signiflcantly from Early-Middle Devonian early diagenetic dolostones (Kleesment & Shogenova 2005;Kleesment 2007;Shogenova et al 2007;Tänavsuu-Milkeviciene et al 2009;Kleesment et al 2012). It is suggested (Stinkulis 1998(Stinkulis , 2008) that main diagenetic alterations in Plavinas rocks took place in already lithified rocks, however, these have not been studied in detail as yet.…”

“…Dolostones may re-equilibrate many times Sorokin (1978) and Suuroja (1997). The stratigraphical scheme ofthe Middle-Upper Devonian boundary beds of Estonia and Latvia modified after Kleesment et al (2012) and Mark-Kurik & Pôldvere(2012).…”

An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia

“…This grain outline does not stand alone within the sediments studied, but yields a significant concentration at numerous localities in the Baltic States . This concentration is likely due to (1) a seasonal freezing or/and action of fluids that can lead to grain splitting (Velichko & Timirieva, 1995) in a periglacial environment and/ or (2) a possible inheritance from corroded and deformed quartz outlines, occasionally fractured and cracked, of the carbonate-cemented siliciclastic rocks of the Devonian Baltic Basin (Kleesment et al, 2012). The deformations present in the upper part of the section (Fig.…”

Understanding a continuous inland aeolian deposition: a closer look into a chronological and sedimentary record of the north-eastern European Sand Belt

“…In general, it is not really clear what causes feldspar contamination. A realistic explanation may be related to the dominance of Silurian and Devonian siliciclastic rocks in Estonia and Latvia, which mineralogically contain between 50% and up to 95% of quartz depending on the formation(Kleesment et al 2012). Since these rocks directly border the…”